An engineering specification or drawing can be wrong. Procurement can substitute a lower cost item not meeting specification. A supplier can substitute non-conforming materials into the supply chain. Quality control can miss something. The change order process can make the wrong decision or make a decision without competent input, etc.
The tops on my construction goofs to resolve had several errors stacked together. The concrete contractor accurately installed an under ground foundation passage for a pipe. The piping contractor connected at the wall penetration and accurately ran his piping through a trench so many feet at a specified angle. Oops, the end of the pile missed the tank connection. Normally, this would be no harm, no foul. That's what elbows and come alongs are for. Oops, the pipe connection missed by a lot. The tank being connected to was a bolted stainless steel tank about 300,000 gallons in size. The panel with the nozzle for the pipe connection was installed in the wrong location. So far, my only grief had been standing between structural and piping contractors blaiming the other for the goof. Fixed that by correctly IDing the root cause to the tank. Had the tank contractor take down the tank and put the panel in the correct location. While this was going on pulling the tank apart, I discovered that the tank manufacturer had also located the nozzle incorrectly on the tank panel. The piping contractor and I huddled and had the tank guy rotate the panel 180 degrees upside down in addition to installing the panel in the correct location on the radius. The pipe guy got a change order for a few more feet of pipe and trench, some additional fittings and welds. The tank guy ate the cost for taking his tank down and reerecting. I added markups to the construction drawings that were rolled up into the as-built drawings at the end of the project. The findings and actions were documented in my daily log and a memo to my engineering and management. A day in the life of a construction manager.
The big change that I have seen over the years is that the top guy on the job usually started with a broom in his hand and learned the business from the ground up. Every stage of it.
Now, most of it is run by kids who never stepped outside in their lives. Their experience comes from whatever the computer tells them. They can’t visualize or realize that what they are doing on the computer doesn’t always work in the real world.